Noodles gets disappeared after joining the two different nodes
I'm 99% that is a bug. Here is how to report it:

In the main menu on the top left click on help, then choose report a bug. It will send you to a page belonging to the developer section of blender.org. You do need a Blender account to file a bug report, but like all the other Blenderstuff: it's free.
Follow the instructions, they are very straight forward. 
And you're done. Congratulations, you helped the Blender community.